An important aspect of the present invention is employing a cooking method which converts an untexturized protein product into a texturized protein using a single cooking vessel. Particularly, the present invention provides a cooking method for an untexturized, paste-like, batter-like protein product with no visible grain or texture into a texturized, coarse, crumbly, protein product with a definite shape having the consistency of cooked ground meat.
The term texture describes a wide variety of physical properties of a food product. A product of acceptable texture is usually synonymous with the quality of a product. Texture has been defined as "the attribute of a substance resulting from a combination of physical properties and perceived by senses of touch, including kinaestheses and mouth feel, sight, and hearing. Texture, as defined by the International Organization of Standardization, is "all of the Theological and structural (geometric and surface) attributes of a food product perceptible by means of mechanical, tactual and, where appropriate, visual and auditory receptors." The following terms have been used to describe product characteristics falling under the umbrella "texture":
TABLE I ______________________________________ ABRIDGED LIST OF FOOD TEXTURE ADJECTIVES ______________________________________ Adhesive Fleshy Mushy Soft Bouncy Fluffy Oily Soggy Brittle Foamy Pasty Sparkly Bubbly Fragile Plastic Splintery Chewy Full-bodied Porous Spongy Clingy Gooey Powdery Springy Coating Grainy Puffy Sticky Cohesive Gritty Pulpy Stringy Creamy Gummy Rich Syrupy Crisp Hard Rough Tender Crumbly Heavy Rubbery Thick Crusty Heterogenous Runny Thin Dense Juicy Sandy Tingly Doughy Lean Scratchy Tough Dry Light Short Uniform Elastic Limp Silky Viscous Fatty Lumpy Slippery Watery Firm Moist Slivery Waxy Flaky Mouth coating Smooth Wiggly ______________________________________
Accelerated attention has been given to texture as it pertains to newer food substances including fabricated and imitation products, formed meat and fish products, where very serious efforts are made by processes to duplicate the properties of the original or other natural food substances. The use of non-traditional raw materials, synthetic flavors, fillers, and stretchers all tend to alter certain textural characteristics of the finished product. Frequently, the imitation of textural properties is of much greater difficulty in the replication of taste, odors, and colors. Numerous manipulative processes, including extrusion texturization, have been developed to simulate natural textural properties. The processes generally find it prudent to duplicate the properties of the original substances to the extent feasible technically and economically in order to promote early market acceptance. While texture has attributes related to appearance, it also has attributes related to touch and also mouth feel or interaction of food when it comes in contact with the mouth. Frequently, these sensory perceptions involved with chewing can relate to impressions of either desirability or undesirability.
Thus, textural terms include terms relating to the behavior of the material under stress or strain and include, for example, the following: firm, hard, soft, tough, tender, chewy, rubbery, elastic, plastic, sticky, adhesive, tacky, crispy, crunchy, etc. Second, texture terms may be related to the structure of the material: smooth, fine, powdery, chalky, lumpy, mealy, coarse, gritty, etc. Third, texture terms may relate to the shape and arrangement of structural elements, such as: flaky, fibrous, stringy, pulpy, cellular, crystalline, glassy, spongy, etc. Last, Texture terms may relate to mouth feel characteristics, including: mouth feel, body, dry, moist, wet, watery, waxy, slimy, mushy, etc.
As used herein, "untexturized" and "texturized" describe the characteristics of the food product as set forth in Table II:
TABLE II ______________________________________ Untexturized Texturized Characteristic Characteristic ______________________________________ Behavior of sticky firm Material under gooey chewy Stress or Strain plastic Structure of smooth coarse Material Shape and gelatinous fibrous Arrangement of pulpy crusty Structural Ele- pasty ments Mouth Feel creamy moist mushy dry with body ______________________________________
It is well known in the art to produce mechanically separated poultry using high-pressure machinery that separates bone from tissue, by first crushing bone and adhering tissue and then forcing the tissue, and not the bone, through a sieve or similar screening device. The process forms an untexturized, paste-like blend of soft tissue with a batter-like consistency.
The prior art methods then cook the paste-like blend and any additives with some agitation to form globs of protein, resembling pieces of liver. These globs are then run through a grinder to obtain a texturized meat product. Texturized meat made from this process suffers from lack of uniform consistency caused by shearing of the protein through the blades of the grinder.
The process of the present invention also utilizes the untexturized, paste-like blend of soft tissue as the starting material; but rather than heat the untexturized blend in a pot, as the prior art does, the inventive process places the untexturized, paste-like blend in a jacketed tub and mixes the blend. During mixing, the untexturized, paste-like blend is in direct contact with injected steam. The inventive process results in a texturized protein product with a more uniform consistency than the product of the prior art, because no shearing mechanism (such as grinding) is involved. The present method provides a definite advantage over the prior art method by eliminating the grinding step, which is necessary when using the prior art method, and utilizing heating by direct contact with steam. The present method also allows a crust to form on the outside surfaces of the protein as it is blended in direct contact with the injected steam.
Utility of the present invention lies in the use of untexturized, paste-like, moisture-carrying protein products, such as comminuted, emulsified or finely ground chicken, lamb, beef, pork, turkey or poultry, to form such useful texturized food products such as taco filler, spaghetti sauce, pizza topping, chile, or the like. Economic gain can be found in providing an inexpensive method of converting comminuted chicken, turkey or poultry, initially in the form of paste, having a batter-like consistency, with little or no visible grain or texture, into a protein product, having the texture of cooked loose hamburger meat. Such product may then be used in a number of prepared foods.
A patent addressing similar objectives is U.S. Pat. No. 4,128,051 (Hildebolt, 1978). The Hildebolt patent discloses a process and apparatus for texturizing vegetable protein to produce discreet pieces of puffy, irregularly shaped protein matter simulating natural meat. The '051 patent discloses a method comprising continuously extruding a tubular shell of semi-rigid, bland protein material into a confined treatment zone; injecting a heated gaseous steam into the interior of the tubular shell as it enters the confined treatment zone to blow the tubular shell into discreet pieces of irregularly shaped protein material; and recovering the texturized protein product. The apparatus utilized in the '051 method for texturizing protein comprises means for continuously extruding a tubular shell of semi-rigid protein dough material into a confining treatment zone; means for injecting a heated gaseous steam into the interior of the extruded tubular shell as it enters the confined zone to blow the shell into discreet pieces of irregularly shaped protein material; and means for recovering the texturized protein material. The Hildebolt patent utilizes a method and apparatus requiring an extrusion die for injecting steam into the interior of the tubular shell.
Other patents which disclose methods for preparing cooked, textured poultry products include U.S. Pat. No. 3,917,860, which discloses a cooked poultry product having the appearance and characteristics of cooked ground meat. The product is prepared by blending raw, comminuted poultry in a textured, vegetable protein and cooking the resultant mixture in a broth. The '860 patent points out the utility of utilizing comminuted chicken products, especially as a substitute for pork and beef products, for use in preparations such as chile, pizza, and spaghetti sauce. The '860 patent also discloses a method of preparing a cooked chicken food product, 70 parts by weight of broth and comminuted chicken blended with 15 parts by weight of unhydrated textured vegetable protein, with the resultant mixture cooked at 170.degree. F. to 212.degree. F. with water, beef bullion, beef stock or salt water. The product is then cooled to provide a cooked, textured chicken product, which is free of any chicken flavor. The resultant product is suitable as a replacement for cooked, chopped beef and various food dishes.
The mixture disclosed in the '860 patent is cooked using a "thermascrew". A steam jacket surrounds a cylinder containing a continuous helical web on a rotating screw. The temperature is kept about 170.degree. F. to 212.degree. F., while the cooked meat exits the thermascrew at about 180.degree. F. Alternatively, the broth cooking can be carried out by batch processing in a suitable kettle at a temperature from about 170.degree. F. to 212.degree. F.
None of the patents, however, disclose a method of simultaneously mixing and heating comminuted chicken to form a texturized product. Following the formation of the textured product by heating, the moisture content may be reduced by pulling a vacuum over the product, causing it to boil off moisture until the desired moisture content is reached.